A novel poly(amidoamine)-modified electrolyte-insulator-semiconductor-based biosensor for label-free detection of ATP

Adenosine triphosphate (ATP) is crucial for cellular activity. The need for ATP detection in the field of biomedicine is on the rapid rise. Several biosensor-based approaches have been developed as a result of the growing demand for ATP detection. An electrolyte-insulator-semiconductor (EIS) sensor is a type of field-effect device that has the ability to detect surface-potential changes with a specific level of sensitivity. In this study, a label-free ATP detection biosensor that is based on poly(amidoamine)-modified EIS sensors was developed, in which ATP-sensitive aptamer (Apt) was utilized as sensitive element and EIS sensor was used as transducer. It is possible to monitor the binding of charged molecules, such as aptamers using EIS sensors in a label-free manner with a straightforward setup. To improve the coupling efficiency of Apt with EIS sensor, positively charged polyelectrolyte, i.e. poly (amidoamine) (PAMAM) dendrimers, was utilized to modify the surface of the EIS sensors to attach the negatively charged Apt based on electrostatic attraction. The adsorptive binding of Apt and ATP results in a change in capacitance of EIS sensor. During the process of surface modification, the electrochemical measurements. of capacitance-voltage (C-V) curves and constant-capacitance (ConCap) characteristics were utilized as indicators for the corresponding processes of EIS sensor surface modification. The measurements results indicated this biosensor was able to detect ATP with high sensitivity and good specificity. The detection range of ATP was 0.1. nM to 100. nM and the detection limit was as low as 0.12 nM. This biosensor has the potential to be utilized in the detection of ATP in the surrounding microenvironment of cells and tissues, which have promising prospects to be applied in the field of biomedicine such as energy and metabolism monitoring of cells and tissues.